(It is a climb). I push slowly on the pedal but the car doesn't accelerate, there are some small hesitations. Suddenly, with the same constant pressure, the car accelerates faster.
And no VTEC at that RPM (12 valves).

Quote:

Do you have NGK ZFR4F-11 spark plugs readily available? If you do, swap those into your car and see if the hesitation is reduced then.

I don?t know, this is normaly not the good spark plugs for Civic VEi. I always had ZFR5F-11 and no problem before.
I think that the spark will be better with ZFR4F-11, perhaps less hesitations, but the heat will be too high (bad for the engine).

And sorry for my bad English, I hope you understand what I want to say lol

(It is a climb). I push slowly on the pedal but the car doesn't accelerate, there are some small hesitations. Suddenly, with the same constant pressure, the car accelerates faster.
And no VTEC at that RPM (12 valves).

That is the motor coming out of "Lean Burn" mode....looked pretty normal and a decent response time of the LAF to me.

Quote:

Originally Posted by VEI

I don?t know, this is normally not the good spark plugs for Civic VEi. I always had ZFR5F-11 and no problem before.
I think that the spark will be better with ZFR4F-11, perhaps less hesitations, but the heat will be too high (bad for the engine).

Does your motor have a sticker on the top timing belt cover that shows the recommended plugs?
Like this (picture from my d15z1):
The lean burn really needs a hot plug to ignite the lean mixture well.

Quote:

Originally Posted by VEI

And sorry for my bad English, I hope you understand what I want to say lol

Your English is very good! And your use of Youtube is a great help as well. Keep it up.

I think that the spark will be better with ZFR4F-11, perhaps less hesitations, but the heat will be too high (bad for the engine).

As I understand it, that middle number is the heat value of the spark plug. Hotter plugs have a deeper well around the center electrode, reducing heat dissipation to the cylinder head which results in a hotter center electrode.
A hotter plug shouldn't cause the engine to overheat, though it's possible it could cause pinging. What's the typical octane rating of gasoline in Belgium?

Are your driving habits the same as when you first had the car? How many kilometers were on the car when you bought it?

66000km

Now : more highway.
But I doesn't have problems on highway because the engine is running at 4000RPM (short gearbox now).

Quote:

Originally Posted by TomO

Could you please post the numbers on the side of your ECU for us as well? I am interested to see if the ECU version is different than the US model.

The Honda reference for my car is : 37820-P07-G02. Is it this number that you want?

Quote:

As I understand it, that middle number is the heat value of the spark plug. Hotter plugs have a deeper well around the center electrode, reducing heat dissipation to the cylinder head which results in a hotter center electrode.
A hotter plug shouldn't cause the engine to overheat, though it's possible it could cause pinging.

I kinda doubt that, but I don't blame you for being cautious. You would have to be running lean under high load to get the piston hot enough to melt. Detonation can break the ringlands off the piston or occationally punch a hole in it, but that generally only happens with cars running aftermarket forced-induction (supercharger, turbocharger, nitrous) systems.

Quote:

Originally Posted by VEI

95 or 98.
For my car : 95.
What is the ocatne rating in US?

87, 89 and 91 are most common, but as high as 95 can be found at some stations.